Datasheet

ADA4896-2/ADA4897-1/ADA4897-2 Data Sheet
Rev. | Page 22 of 28
MEDICAL ULTRASOUND APPLICATIONS
BEAMFORMER
CENTRAL CONTROL
Rx BEAMFORMER
(B AND F MODES)
COLOR
DOPPLER
PROCESSING
(F MODE)
IMAGE AND
MOTION
PROCESSING
(B MODE)
SPECTRAL
DOPPLER
PROCESSING
MODE
DISPLAY
AUDIO
OUTPUT
Tx BEAMFORMER
TRANSDUCER
ARRAY
HV
MUX/
DEMUX
T/R
SWITCHES
AD9279
AAF
VGALNA
ADC
09447-033
CW (ANALOG)
BEAMFORMER
ADA4896-2/
ADA4897-1/
ADA4897-2
Figure 54. Simplified Ultrasound System Block Diagram
Overview of the Ultrasound System
Medical ultrasound systems are among the most sophisticated
signal processing systems in widespread use today. By transmit-
ting acoustic energy into the body and receiving and processing
the returning reflections, ultrasound systems can generate images
of internal organs and structures, map blood flow and tissue
motion, and provide highly accurate blood velocity information.
Figure 54 shows a simplified block diagram of an ultrasound
system.
The ultrasound system consists of two main operations: the
time gain control (TGC) operation and the continuous wave
(CW) Doppler operation. The AD9279 integrates the essential
components of these two operations into a single IC. It contains
eight channels of a variable gain amplifier (VGA) with a low
noise preamplifier (LNA), an antialiasing filter (AAF), an
analog-to-digital converter (ADC), and an I/Q demodulator
with programmable phase rotation. For detailed information
about how to use the AD9279 in an ultrasound system, see the
AD9279 data sheet.
B